Numerical investigation on the effects of downstream pipe flow of bellmouth entrance

In flow systems such as fan, pomp, compressor and air ducts, it is accurately important to calculate the energy loss as much as decreasing the energy loss. In the study, a numerical work has been made to reduce the energy loss at the pipe entrance. When fluid flows from a reservoir towards pipe, pipe inlet has essential effects on downstream flow properties.In applications, it is seen that bellmouth pipe entrance, protruding pipe entrance and sharpedged pipe entrance have been used. Bellmouth entrance enables to form uniform velocity profile of fluid towards pipe therefore it has been stated in the literature that it has low turbulence properties and the lowest energy loss material in comparison of other pipe entrance types. Bellmouth flow entrance can considerably improve the performance of devices such as fan, compressor and internal combustion engine. Bellmouth entrance types can be designed in three different ways which are elliptical, aerofoil and round radius. In the thesis, the best performance of elliptical bellmouth entrance types on geometrical parameters of fluid was investigated. Due to the above-mentioned reasons, nine different geometric dimensions of bellmouth entrance have been designed with the same radius. These bellmouth dimensions are in the range of 0.34 < L/De < 0.8 of non-dimensional bellmouth. Numerical method has been used for solutions of these bellmouth dimensions in the range of 20000<Re<100000 of Reynold numbers in a condition of constant and isothermal liquid flow. Turbulence flows were solved with the RANS equations and SST k-omega model. The results obtained from the numerical calculations, the effects on pipe entrance velocity profile of L/De ratio, local friction load loss of bellmouth material, Darcy friction factor in pipe flow and axial flow rate were analyzed. As a result, L/De ratio had no effect on turbulence pipe flow but it had on laminer pipe flow. It was observed that the changes of L/De ratio at pipe entrance had influence in velocity profile. It was seen that the changes of average flow velocity at pipe entrance had irregular effect for L/De and Re. The same of Reynold numbers were used for sharp-edged pipe as a comparison preference. It was observed that the velocity profile and downstream characteristic of sharp-edged at pipe entrance were very different and the values were insignificant in terms of pressure loss compared to bellmouth entrance. As a result, the best L/De ratio of bellmouth entrance were recorded thanks to this numerical research.